As wireless access terminals and wireless communication networks continue to evolve, there are now several concurrently deployed radio access technologies (RATs). In many instances, individual RATs may also have multiple concurrently deployed versions. Newer RATs and newer RAT versions generally offer benefits, such as faster data transfer, compared to prior RATs and prior RAT versions. Many modern access terminals have a multi-mode capability, and can connect to a network using multiple RATs and/or multiple versions of one or more RATs. Likewise, many radio access networks support multiple RATs and/or multiple versions of one or more RATs. As such, when an access terminal establishes a session with a radio access network, the access terminal and radio access network can negotiate a session personality defining one or more RAT versions (e.g., one or more particular RATs and/or one or more particular versions thereof) to use during the session.
Wireless operators typically have roaming agreements with operators in different countries to enable accessibility of voice, data and other supplementary services for their subscribers when they travel internationally. Roaming agreements can be between operators that use the same underlying RAT or between operators using different underlying RATs. For example, a Third Generation Partnership Project 2 (3GPP2) (CDMA2000 and HRPD) operator using CDMA2000 and/or High Rate Packet Data (HRPD) RATs can have roaming relationships with other 3GPP2 operators and/or with a Third Generation Partnership Project (3GPP) operator that can use Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), and/or Long Term Evolution (LTE) RATs.
Cross technology agreements often require that an access terminal support multiple technologies. Terminals that support multiple technologies are referred to as multi-mode devices. However, a multi-mode device is typically not inherently entitled to service in any country to which a user travels. Instead, a roaming agreement between the operator of the terminal's home network and the operator of the roaming access network is typically required.
If the roaming access network and an access terminal negotiate a session personality allowing use of a RAT version that is not covered in the roaming agreement between the operator of the roaming access network and the operator of the home network of the access terminal, several problems can result. For example, in some instances, if a RAT version that is not covered by the roaming agreement is a preferred RAT version that is supported by both the access terminal and the roaming access network, the access terminal may become stuck in a loop in which the access terminal and roaming access network may negotiate to use the RAT version in a session and then experience session failure due to lack of support for the RAT version in the roaming agreement. As another example, in some instances, if an access terminal and roaming access network negotiate a session personality in which a first RAT version, which is not covered by the roaming agreement, and which provides faster data rates than a second RAT version that is covered by the roaming agreement, the roaming access network may essentially give away additional bandwidth and/or other services for which the roaming access network may not be compensated by the home network.